During the first century AD, the Celts of Switzerland were incorporated into the Roman empire. This study shows the changes in the consumption of meat which were an expression of the new economic system established during the two following centuries. The evidence stems from approximately 200,000 animal bone fragments from over 140 stratified and reliably dated complexes from areas north of the Alps. The inhabitants of Celtic settlements subsisted on extensive agriculture. The great increase in population during Roman times led to an intensification of agriculture. ln Celtic settlements, cattle bones are found less frequently than in Roman ones whereas sheep and goat bones occur more often. There are hardly any discernible differences between late Celtic and early Roman military settlements, which may however be due to the way in which the evidence has been presented. During the course of the first century AD, first changes in the meat diet can be observed in the newly established Roman settlements. Beef became considerably more important in the second and third centuries whereas sheep and goat meat became less important.